<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		div {
			border:1px solid red;
			display:inline-block;
			padding:10px;
		}
	</style>
</head>
<body>
	<script>

		var arr1 = ['1','2','3','1','2','3','1','2','3'];
		function qc (arr) {
			var obj = {},len=arr.length,x;
			for (var i = 0;i < len;i++) {
				obj[arr[i]] = arr[i];
			}

			arr.length = 0;

			for (x in obj) {
				arr.push(obj[x]);

			}
			return arr;
		}
		var r = qc(arr1);
		console.log(r)


	</script>
</body>
</html>
